bn/bn_exp.c: harmonize BN_mod_exp_mont_consttime with negative input. #4676
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All exponentiation subroutines but BN_mod_exp_mont_consttime produce non-negative result for negative input, which is confusing for fuzzer.
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Since this is called the consttime version, does this change anything in this being consttime? |
No. Well, it's a trick question. I can't see that BN_mod or BN_nnmod are constant-time, but in real life applications such as RSA inputs are reduced [and positive], so that they are not called. EDIT: Bottom line is that constant-time-ness is not changed. |
paulidale
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All exponentiation subroutines but BN_mod_exp_mont_consttime produce non-negative result for negative input, which is confusing for fuzzer. Reviewed-by: Paul Dale <paul.dale@oracle.com> Reviewed-by: Kurt Roeckx <kurt@roeckx.be> (Merged from openssl#4676)
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All exponentiation subroutines but BN_mod_exp_mont_consttime produce
non-negative result for negative input, which is confusing for fuzzer.